Sheet Skew Correction Guide Structure for Stable Conveyance
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Solution Overview
Problem
Existing image forming apparatuses face issues with unstable sheet orientation and conveyance failures due to the re-engagement of pre-registration roller pairs after skew correction, leading to potential slip and conveyance issues.
Innovation Solution
A sheet conveyance apparatus with a skew correction mechanism using a pair of abutment portions and a guide portion that corrects skew by forming a wave in the sheet's leading edge, enhancing rigidity and reducing loop formation, allowing stable conveyance without reliance on external forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the pre-registration roller pair is separated to reduce loop pressure during skew correction, then loop pressure is reduced, but sheet orientation becomes unstable and conveyance failure occurs
Solution Approach 1:
The guide portion is configured to be movable between a guide state during skew correction and a separated state during normal conveyance. This dynamic adjustment allows the system to reduce loop pressure when needed while maintaining stable conveyance when the guide portion is separated, resolving the contradiction between pressure reduction and conveyance stability.
Solution Approach 2:
The guide portion acts as an intermediary element that can be selectively engaged or disengaged. When engaged, it provides guidance during skew correction; when disengaged, it allows stable normal conveyance. This intermediary mechanism enables the system to switch between different operational modes, resolving the stability issue.
2Productivity
If the pre-registration roller pair re-engages after skew correction, then conveyance can resume, but orientation instability and slip occur
Solution Approach 1:
The guide portion dynamically transitions from an engaged guide state during skew correction to a separated state during normal conveyance. This dynamic separation prevents the orientation instability and slip that occur when the guide structure remains engaged, while still allowing conveyance to resume through the separated guide configuration.
3Manufacturing precision
If a guide structure is used during skew correction, then skew correction is effective, but the structure becomes complex
Solution Approach 1:
The guide portion is designed to be movable between engaged and separated states, allowing it to provide guidance only when needed for skew correction. This dynamic design reduces overall structural complexity compared to a permanently engaged guide structure, while maintaining skew correction effectiveness when required.
Solution Approach 2:
The guide portion is extracted as a separate, movable component rather than being integrated into the fixed structure. This extraction allows the guide function to be selectively applied only during skew correction, reducing the complexity of the overall system while maintaining correction accuracy.
Data Source
AI summary
A sheet conveyance apparatus includes a conveyance rotating member pair to convey a sheet in a sheet conveyance direction, and a skew correction portion including a first abutment surface having a first root portion and a second abutment surface having a second root portion. A guide portion includes a guide surface disposed between the first abutment surface and the second abutment surface. The first root portion is positioned within a first recess portion disposed upstream of the first abutment surface such that a leading edge of the sheet enters the first recess portion upon abutting against both the first abutment surface and the second abutment surface, and the second root portion is positioned within a second recess portion such that the leading edge of the sheet enters the second recess portion upon abutting against both the first abutment surface and the second abutment surface.